This invention relates to a continuous process for producing clean streams of synthesis or fuel gas by the partial oxidation of a hydrocarbonaceous fuel with a free-oxygen containing gas. More specifically, it relates to an improved procedure for recovering the particulate carbon entrained in the hot raw effluent gas stream from a free-flow noncatalytic partial oxidation gas generator and producing a clean dewatered stream of synthesis or fuel gas and a separate clean stream of synthesis gas saturated with H.sub.2 O.
Raw effluent gas leaving a partial oxidation gas generator may comprise principally CO, H.sub.2, CO.sub.2 and H.sub.2 O together with other gaseous impurities and minor amounts of entrained finely divided carbon and ash. The particulate carbon is commonly referred to as soot. Cleaning and purifying the raw effluent gas to produce synthesis gas or fuel gas usually starts with the removal of the particulate carbon and any other entrained solids. This will extend the life of any catalyst or solvent that may be later contacted by the process gas stream. Synthesis gas is important commercially as a source of feed gas for the synthesis of hydrocarbons or oxygen containing organic compounds, or for producing hydrogen or ammonia.
Entrained particulate carbon may be removed from the raw effluent gas by quenching and scrubbing with water such as described in coassigned U.S. Pat. No. 3,232,728. Cleaning the effluent gas by scrubbing with an oil-carbon slurry is described in coassigned U.S. Pat. No. 3,639,261. Recovery of the particulate carbon from carbon-water dispersions by the steps of adding a light oil to the carbon-water dispersion, separating water and light oil-carbon dispersion in a decanter, mixing the light oil-carbon dispersion with heavy oil and heating in a preheater, and vaporizing the light oil in a flash drum or distillation tower is described in coassigned U.S. Pat. Nos. 2,999,741; 2,992,906; 3,044,179; and 4,134,740. However, in these processes in contrast with the subject process, there is no direct contact between the liquid organic extractant-carbon-water dispersion and the main source of heat. Accordingly, the subject process is more thermal efficient and eliminates costly equipment, i.e. distillation towers, coolers, and flash separators. Typical decanting procedures are described in coassigned U.S. Pat. Nos. 3,980,592 and 4,014,786.